Rail steel



Io Drawing.

Patented Aug, 26, 193C! UNITED STATES.

JOSEPH main man, or nnrnorr, lncnmm, .nssrenon, er sesssnissmmem, 'ro

emu 130R. comm, n coaronnrmn' or n cnman This inventign relates-to rail steels and its nature, otglg'ects and advantages will be best underst from the following: It is well known that in plain carbon steels, otherwise of equal quality, wroughtand not heat treated, as the percentage of carbon and of manganese rises their strength and rigidity increase, while at the same time their static,

ductility decreases and their resistance to im pact decreases mucli'more rapidly still. As static rigidity and Brinnell hardness increase, so does the resistance to wear in such steels increase. The relation of strength to a given percentage of carbon and/or manganese is relative to'the method of steel making employed; In other words, fora given percentage of carbon and/or manganese, steel made by the acid gas open hearth process is somewhatstifler than is'steel made by the basic' gas open hearth process and steel made on the electric hearth is stifier than either.

Itis also well known by long experience in.-

' rail malnngthat taking such a specification (a) Greatly increased strength as is in common use for a rail weighing 100 pounds per yard, the carbon percentage should not appreclablyv exceed .70 percent and from-.70 to 1.00 per cent manganese, and

it' is the common practice as the carbon is ralsed to come down 1n the manganese 1n order to pass the drop test.

With the foregoing brief statement of the standard practice in rail making in mind,it

the object ofthe present invention,-stated 1n general terms, to obtain either ance to wear with a given impact-resistance,

(b) Greatly increased impact-resistance with a given strength and rigidity.

Stated in other words, I either c (a) May employ percentagesof carbon and manganese which would today be regarded and resist-- Appileation fled number-24, 1925; "Serial "m; 71,220.

as inordinately high, and secure steel greatly increased strength andsresistance-to wear, whichsteeh'however, will still have approximately the same impact resistance as standardraihsteels, or 1; 1 v i 1 '(b) -May em loy approximately the same percentages of arbon and manganese as. in

standard practice, and ,s'ecu're :a steel: withgreatly increased impact, resistance, which steel, however, will :have approximate'ly f the same strength and rigidity: as standard rail steels. 1

I- have found that-if, in making thesteel of my invention, I employ .egranularviron as a base: in whole or-xinrpart,1i. :;e., iron tain the foregoing properties. wThis iron contains no ierrite-dissolved-nitrides,- and. if v I wish to secure greatly :increased strength and resistance to wear, with' approxlmately the same ductilitycand -7resistance-impact: as

instandardrail steels, I increase the'carbonmanganesecontent, andaifal'i-desire approximately the same strengthiandz ductility as 1s customary, with the greater resistance to 1m- 'pact thanis the case in ktandardfipractice, 'I

employ the usual percentages-"of the carbonmanganesecomplexx. As illustrative of the properties ofsuch :a rail steel, I have'tested rai ls ofi'th e steel as made in the electric furnace-andi'contalm ing .79per cent carbon and 1.08 per cent manganese'. The rails tested to an increase of about 20 per cent in strength, a greatly increased rigidity, and a corres ondingly ncreased hardness, notwithstan ing which the rail not only withstood the prescribed drop test with ease but was able towithstand repetitions of the test well beyond the point at which the softer or conventional rail steel failed. The result obtained with these test pieces was allthe more remarkable because the steel was'cast into a small ingot and rolled down only to the size of 100 pounds per yard, in consequence of whichthe bars were not worked nearly as extensivelyas would be the casein normal rail manufacture.

I give as the preferred range of carbon and characteristics, carbon from .60 per cent to i .90 per cent and manganese from .7 per cent to 1.25 per cent.

l The granular iron referred to may be made by the method disclosed in Hornsey apphcation Serial-No. 532,486,.fi1ed January 28,

1922. The Hornsey method as disclosed in said application discloses a process of reducing iron oiride bearing materials to iron without melting, involving the introduction of the ore in a fine state of division into the upper end of the gas sealed apparatus. The apparatus disclosed includes three rotary cylinders. In the first the ore is preheated to approximately the temperature of reaction To the preheated ore is added a mixture of solid carbonaceous reducing agent in a fine state of division. The. mixture of ore and fine carbonaceous material is passed through a second cylinder in which reduction takes place. The gases from the second or reducing c"linde1"* are passed to the preheating cylin er where they are burned to effect the j preheating. The reduced material from the second cylinder is passed to a third cylinder which is preferably'water cooled. This cylinder reduces the temperature of the reduced product to such a point'that it 'will not readily reoxidize by exposure to air.

From what has been said it is believed that those skilled in the .art will appreciate the advantages of the invention. The invention may-be applied to types of steel other than rail steel.

What I claim is 1. Rail steel embodying iron which is free from ferrite dissolved nitrides as a base and carbon appreciably above .70.percent with manganese not lower than customary for .70 er cent carbon.

'2. Rail steel embodymgosolid produced iron which is free from ferrite dissolved nitrides as a base and carbon appreciably above .7 U per cent and manganese appreciably above per cent.

In testimony whereof, I have hereunto signed my name.

J. KENT SMITH.

solid produced 

